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Author Topic: Driving 8ft , 5/8" ground rods into rocky soil, Milwaukee to the rescue.  (Read 37082 times)
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KC2YOI
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« on: July 08, 2010, 02:10:55 PM »

The geology around and under my QTH is a nightmare to penetrate when grounding.
My resistance readings to earth were way off so I started poking around

 I discovered that my panel/service ground rod was only 3 ft long! Who ever did the deed gave up on penetrating the ancient sea bed strata here and just cut it flush in the 1950's  Undecided

Enter the Milwaukee HD hammer Drill, 5 new 8' grnd rds, bronze clamps and 45 feet #6 utility type solid copper wire.

I won't say it was easy but I was able to shatter the shale strata and send 4 of the 5 rods straight down. The 5th went in at a 45* angle

Spaced at 8ft +/-, a zig-zag pattern takes advantage of what moist soil I have and the limited space between the house and drive.

Not being Ideal soil, I'm hoping the multiple spots will help. There is a lot of natural ground water that rides along the plates of rock about 5ft down so who knows?

I finished in the dark and will pick up with new resistance readings Friday.
                                              

                                                     Blah blah blah...  DJ


( the feeder line pic is right above the new ground rods )

  

 

 


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w3jn
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« Reply #1 on: July 08, 2010, 02:18:16 PM »

Hope you drove 'em 16' apart; it's generally accepted that a ground rod's "sphere of influence" is twice its length.
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KC2YOI
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« Reply #2 on: July 08, 2010, 02:26:35 PM »

Avg. is about 12 ft apart in a 6ft wide zig zag to work in the space I have.

I can add more but only in straight lines away from the shack and service panel rod.
I'll keep the 16' rule in mind Friday. Thanks,   DJ

PS Nice new wheels man  Cool
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w3jn
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« Reply #3 on: July 08, 2010, 02:28:09 PM »

TNX.  And great idea using the hammer drill to drive those SOBs.  It's always a pitiful job...
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KE6DF
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« Reply #4 on: July 08, 2010, 03:07:36 PM »

We have an even worse problem out here.

The soil consists of 4in diameter smooth granite river rocks with each rock separated by about 2 inches of soil from the next rock.

I don't think a hammer drill would work.

Planting trees around here is a PITA.

I was thinking perhaps I'd write a new Sunset gardening book for home owners in this area.

The title: "Landscaping with Dynamite"
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KM1H
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« Reply #5 on: July 08, 2010, 04:09:09 PM »

Solid granite is 12-20" down here so I drove a pair in almost horizontally right under the roof dripline. No 16' rule used here, about 10' apart and tied together with #6 solid back to the panel.  The utility company uses a rotary drill and just stuffs them in the hole by pounding.

At a past QTH I used 3/4" L grade copper pipe and a hose to do the work. Went down 2 sections for 20' in sand.

Carl
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KC2YOI
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« Reply #6 on: July 08, 2010, 04:13:14 PM »

re:  "Landscaping with Dynamite"

OOOooohhhh I wish I had a permit for that!!! Grin

Give a big rental vibe hammera shot. I noticed when I floated the hammer off the pin a bit I would get other harmonics that helped get the rod moving again.
Pushing harder only slowed it down... ( like getting my dog in the car to hit the road! )

Carl, the hydro-aproach would work FB on Long Island soil.
Also, some one should come up with a ground rod that has a Tungston Carbide tip for a rotary/hammer drill as you mentioned.... Get er' in


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4cx250
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« Reply #7 on: July 08, 2010, 04:36:57 PM »

Hello Everyone,
 

     I also used a hammer drill to put in ground rods. I can't belive how easy it was!

     Drllled  hole for the rod at the base of a TX in the cement, and the drill did ALL the work. Very easy!

Tnx,

     
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The Slab Bacon
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« Reply #8 on: July 08, 2010, 10:03:33 PM »

A LARGE hammer drill definately gets er done without killing ones self. My big Hilte TE-65 (all 40lbs of it) has a hammer only function. It kicks butt and takes names. an Electrician friend of mine told me about that 15 or 16 years ago when I was bitchin about driving a ground rod. Especially if you have to sink one into the rubbery-assed clay that we have around here.

But here is a thought for you rocky terrain people. Since most modern ground rods are just coppa plated steel. Driving them through rocks is definately gonna tear a good bit of the coppa plating off. If you have acidic ground water, I wonder how long it will take to eat up the steel rod??

You may want to consider replacing them periodically, just for good luck (and good grounds) especially if your counting on them for lightning protection as well.

that may be why your service ground rod was only 3' long, It may have just rotted off to that length!!

                                                        The Slab Bacon.
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ka3zlr
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« Reply #9 on: July 08, 2010, 10:18:05 PM »

Howdy,

 I had Two ground rods in plus the house so that gave me three an then I got that strike on the end of the house where the two were  spread out an connected an some of that charge come in backwards on my grounds I lost my Ten-Tec Pegasus an a 30 Amp DC supply arched into my Viker II it sat beside everything an what surprised me the only thing that was on an connected was my Gateway and It's fine Figure that one out.. Cheesy....Sooooooo.....I Disconnect Grounds to now..

 I pulled everything an rehooked onto my 1600 ft 3/4" Copper water line thats buried a meter under ground goes down through the hayfield an to the road an have (fingers crossed) experienced no problems so far an some RFI issues disappeared so I reckon mines worken....  Grin

73

Jack.

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KB2WIG
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« Reply #10 on: July 08, 2010, 10:23:49 PM »

Has anyone thought of digging a few shallow trenches and placing copper   STRAP  inside?


klc
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What? Me worry?
WBear2GCR
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Brrrr- it's cold in the shack! Fire up the BIG RIG


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« Reply #11 on: July 08, 2010, 10:43:40 PM »


I have thought of it... only I was going to get some stainless strips cut offs from a sheet metal place, and spot weld them together (I heard a bolt or two is good in addition) and run as many feet of that as I can at a relatively shallow depth... that idea was for my tower installation...

Can anyone think of a reason NOT to use stainless like this??

                   _-_-bear
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KF1Z
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Are FETs supposed to glow like that?


« Reply #12 on: July 08, 2010, 10:45:28 PM »

Seems to me if you're going through all that trouble to install multiple rods...
You'd use something a bit larger than tiny #6 wire?

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KB2WIG
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« Reply #13 on: July 08, 2010, 11:04:33 PM »

B,
I'd wonder about the conductivity of the steel spotwelds....  Don't have much usefull information to add... worth a try......



klc
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ka3zlr
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« Reply #14 on: July 08, 2010, 11:17:28 PM »

You could bury a coupla radiators if ya have them outta old junk cars, but if it was me with that kinda rock Strata situation why not dig down a coupla feet an bury some copper pipe in all four directions as far as ya can, I've noticed my receive on 160 is a much better now with the Copper water pipe hooked in.

73

Jack.

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Steve - WB3HUZ
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« Reply #15 on: July 09, 2010, 09:01:19 AM »

Wow! The EPA would have your head on a plate. Don't let the neighbors see you bury those radiators.
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KM1H
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« Reply #16 on: July 09, 2010, 09:06:18 AM »

I forgot to mention that I also bonded all the copper water and heating pipes together and to the panel.
As far as #6 copper that is per NEC specs.

I suppose I should go to #00 welders cable when I build the big amp Grin

Carl
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KC2YOI
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« Reply #17 on: July 09, 2010, 09:37:49 AM »

Wow! The EPA would have your head on a plate. Don't let the neighbors see you bury those radiators.

Hey, Iffin they're goodnuff for brewin shine there goodnuff fer ground work  Tongue

I actually knew folks near Anniston AL where I was stationed that condensed corn liqueur w/ used car rads. The local health dept. folks had warning posters in the grocery and dime stores warning about it in the 80's.
I always wondered if the copper leachate was what gave some of that hooch it's blue hue.

I would steer clear of car radiators in the soil.   Cool
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KC2YOI
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« Reply #18 on: July 09, 2010, 09:55:34 AM »

( Whoops, I double posted, I can't delete this, sorry )

Bear, what I can tell you is that a spot welds' dia. is equivalent to the same diameter bolt in terms of strength, ie.  pull and sheer. PLUS it's fused for a virtual corosion proof connection.
As far as stainless, I would guess that extra surface area and guage would make up for the difference compared to copper but that's a guess. I'm not sure either about electrolysis.

I want to pick up some "Thermit" fusion blocks. It goes under other names but works the same. Ground rods/wire/ribbon are wrapped together as you want them and this clay like material is ignited. Once the white hot blue/green flame goes out the pieces are fused.       Really cool stuff!

http://www.railway-technology.com/contractors/electrification/lpi/lpi3.html

Enhanced chemical grounding is interesting also:

http://www.erico.com/products/ChemRod.asp
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WBear2GCR
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Brrrr- it's cold in the shack! Fire up the BIG RIG


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« Reply #19 on: July 09, 2010, 10:22:41 AM »


That outfit is in Tasmania??

But anyhow... I suspect that you can't buy that stuff over-the-counter in the USA these days...

            _-_-bear
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KC2YOI
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« Reply #20 on: July 09, 2010, 10:25:09 AM »

Sure you can.

http://www.youtube.com/watch?v=hqkb30m5IEA

I'll source it and post it.
                                 D.
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ka3zlr
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« Reply #21 on: July 09, 2010, 10:56:46 AM »

)I wonder what happened to my Remove Icon(


  Welp,

 Anything for a ground, drilling through rock is one way I guess I hope it gets Damp alot for ya in dry seasons it can be a bear. I always went by the rule ground does not have to be deep, or just using ground rods..Hmm Hmm nope nope nope,...Area connection is what's important in the ground Lots of area covered like burring in 4 directions some copper pipe in as large cross as you can make.

 I have two friends one uses his well casing that's covered up in the back yard he lives on an old farm like me, an my other friend who lives on another farm did throw a coupla tractor radiators in the ground he rinsed them out good with arm an hammer an water mix then sand blasted them an in the ground they went....connected together how about that copper is copper....Brass is Brass use what's on hand. Cheesy

 But whatever transpires with this ground, disconnect it when you go on vacation as well as your station pull all plugs an all connectors leave nothing to make a trail to follow...

Take it from someone who's been hit twice.

73

Jack.
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KB2WIG
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« Reply #22 on: July 09, 2010, 12:35:08 PM »

FWIW,

YA can go to the local radiator repair service  They can tank the radiators to clean out the scale, balanitis, and other crud.


klc
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Fred k2dx
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« Reply #23 on: July 09, 2010, 05:18:27 PM »

If you are concerned about wearing the copper plating off the ground rods, there are solid brass ones available. At least they used to be... ICE sold them and they weren't outrageously priced at the time. http://www.iceradioproducts.com/

When I had my foundation reparged I took advantage of the 8' deep excavation around the house and drove ground rods starting at the bottom of the ditch, put them around the perimeter, joined in a ring with 00 copper. This is not tied into the AC service ground, but is tied into the tower ground system with copper strap, 00 copper cable, and some other radials made from junk 7/8 copper heliax (with the plastic jacket stripped off, makes a good big surface area conductor).

Overkill maybe - but I've had several strikes on the tower over the years.  
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w1vtp
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« Reply #24 on: July 09, 2010, 09:32:06 PM »

DANG!!! Grin Grin Grin

I gotta have me one of those kool power tools.  I have one ground rod right now and have a buch to go
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